Frequency Sort and Is Subset Of

FrequencySort.js

var frequencySort = function(s) {
  var arr = s.split('');
  var obj = {};
  var results = [];
  for (var i = 0; i < arr.length; i++) {
    obj[arr[i]] = 0
  }
  for (var j = 0; j < arr.length; j++) {
    if (obj[arr[j]] !== undefined) {
      obj[arr[j]]++;
    }
  }
  var sorted = '';
  for (var key in obj) {
    while (obj[key] > 0){
      results.push(key);
      obj[key]--;
    }
  }
  return obj;
};

isSubsetOf.js

var isSubsequence = function(s, t) {
  let counter = 0;
  for (let i = 0; i < s.length; i++) {
    for (let j = 0; j < t.length; j++) {
      if (s[i] === t[j]) {
        counter++;
        t = t.slice(j,t.length);
      }
    }
  }
  if (counter === s.length) {
    return true;
  } else {
    return false;
  }
};